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Natural gas: study raises doubts on U.S. supply

May 17, 2011 | 4:35
pm

The United States does not have a decades-long supply of inexpensive, locally sourced natural gas, according to a new report commissioned by the Post Carbon Institute, a nonprofit think tank that examines issues related to the economy, energy and the environment.

The report, titled "Will Natural Gas Fuel America in the 21st Century?," is a challenge to the commonly cited projection that domestic natural gas can meet U.S. demand for more than 100 years. It comes on the heels of the U.S. Energy Information Agency's 2011 Energy Outlook released last month that projected an almost fourfold increase in domestic shale gas production by 2035 and growing use of natural gas to generate electricity.

"The question is what would it take in order to do that?" said study author David Hughes, a geoscientist who serves on the board of the Assn. for the Study of Peak Oil and Gas-Canada and is a fellow at the Post Carbon Institute in Santa Rosa, Calif.

Hughes estimates there is only a 12-year supply of easily accessible, domestic natural gas. He said the number of producing gas wells almost doubled from 1990 to 2010, but the productivity of each well has declined nearly 50% over the same 20-year period.

"More and more infrastructure will be necessary to maintain productivity," Hughes said. "One has to drill a huge number of wells to keep production going."

Until 2006, about 10,000 gas wells were drilled each year. Even with the current rate of 25,000 wells per year, "I don't think that's enough drilling to continue growing gas production," said Hughes, adding that "reserves have been greatly overstated."

According to the nonprofit Potential Gas Committee, a volunteer organization overseen by the Colorado School of Mines, U.S. natural gas resources increased by more than 900 trillion cubic feet between 2000 and 2011 to 2,100 trillion cubic feet.

"Even as we’ve been drawing trillions of cubic feet out of the ground and thus out of the resource base, the resource assessment continues to grow," said Daphne Magnuson, spokeswoman for the Natural Gas Supply Assn. in Washington, D.C.

Magnuson said natural gas is far easier and more economical to access than it was a decade ago with conventional wells, which explains the dramatic projections of reserves. More than 20 states have natural gas shale deposits.

"We continue to discover more at such a rapid rate that shale maps are quickly outdated," she said. "The natural gas industries consider the U.S. 'the Saudi Arabia of natural gas.'"

But according to Hughes of the Post Carbon Institute, growing U.S. natural gas production would require at least 30,000 wells per year, and "there's likely to be major impacts environmentally that go along with that supply grid," he said.

Numerous environmental groups have raised concerns around groundwater contamination and the improper treatment of the fluids used in hydraulic fracturing, or fracking, to extract natural gas from shale. The U.S. Environmental Protection Agency is investigating hydrofracking and will release its study of the practice in late 2012.

"The nature of natural gas as a clean bridge fuel to renewable energy is highly suspect because of its environmental footprint, lack of ability to scale and full-cycle greenhouse gas emissions" that could be exponentially worse than coal in the short term, Hughes said.